Abstract Pennsylvanian strata of western Pennsylvania exhibit evidence of a hierarchy of paleoclimatic changes. Long-term (10 7 years) climate trends reflect plate movement and tectonic events. These long-term trends are overprinted by changes of much shorter duration (100–400 k.y., and 10–20 k.y.). During deposition of the Pottsville and Allegheny formations (Bashkirian-Moscovian), the Appalachian climate exhibited perhumid to humid situations during periods of glacial advance, and humid to dry subhumid conditions during glacial retreats. Marine faunas and coal swamp floras during this interval of time exhibited a remarkably consistent taxonomic and ecological structure. Tetrapod amphibian faunas were highly aquatic. When the Cone-maugh Group was deposited, the ancient Appalachian climate became progressively drier. Glacial stages were dry subhumid and during deglaciation semiarid to arid. This reduction in precipitation produced changes in coal-forming floras, as lycopsid-dominated assemblages gave way to tree fern–dominated associations. Coincident with this climatic drying, tetrapod faunas became highly terrestrial in the basin. During the deposition of the Monongahela Group, the Appalachian climate returned to humid conditions during glacial periods. However, there is evidence of drier subhu-mid conditions during the intervening interglacial episodes as indicated by the pervasive presence of mudcracked nonmarine limestones. Nested lacustrine cycles within the Monongahela Group indicate short-term alternations between wet and dry periods that may have been driven by Earth’s precession. Coal-forming mires continued to be dominated by tree ferns, and vertebrate faunas tended to be found within fluvial lake environments. The latest Pennsylvanian and/or early Permian strata exhibit a return to Conemaugh-like deposition as evidenced by the pervasiveness of redbeds, dry climate floras, and highly terrestrial vertebrate faunas.

Abstract Pennsylvanian strata of western Pennsylvania exhibit evidence of a hierarchy of paleoclimatic changes. Long-term (10 7 years) climate trends reflect plate movement and tectonic events. These long-term trends are overprinted by changes of much shorter duration (100–400 k.y., and 10–20 k.y.). During deposition of the Pottsville and Allegheny formations (Bashkirian-Moscovian), the Appalachian climate exhibited perhumid to humid situations during periods of glacial advance, and humid to dry subhumid conditions during glacial retreats. Marine faunas and coal swamp floras during this interval of time exhibited a remarkably consistent taxonomic and ecological structure. Tetrapod amphibian faunas were highly aquatic. When the Cone-maugh Group was deposited, the ancient Appalachian climate became progressively drier. Glacial stages were dry subhumid and during deglaciation semiarid to arid. This reduction in precipitation produced changes in coal-forming floras, as lycopsid-dominated assemblages gave way to tree fern–dominated associations. Coincident with this climatic drying, tetrapod faunas became highly terrestrial in the basin. During the deposition of the Monongahela Group, the Appalachian climate returned to humid conditions during glacial periods. However, there is evidence of drier subhu-mid conditions during the intervening interglacial episodes as indicated by the pervasive presence of mudcracked nonmarine limestones. Nested lacustrine cycles within the Monongahela Group indicate short-term alternations between wet and dry periods that may have been driven by Earth’s precession. Coal-forming mires continued to be dominated by tree ferns, and vertebrate faunas tended to be found within fluvial lake environments. The latest Pennsylvanian and/or early Permian strata exhibit a return to Conemaugh-like deposition as evidenced by the pervasiveness of redbeds, dry climate floras, and highly terrestrial vertebrate faunas.

Abstract This paper presents a summary of palynological data for Pennsylvanian age coal beds in the Appalachian Basin, discussed primarily from a biostratigraphic perspective. Coal bed palynofloras of Lower Pennsylvanian through early Permian age are compared and correlated with miospore assemblage zones established for western Europe, and the Eastern Interior (Illinois) and Western Interior Basins of the mid-continent USA. Lower Pennsylvanian palynofloras, which are dominated by lycopsid spores, are correlative with the Langsettian of western Europe and the Morrowan of the Eastern and Western Interior mid-continent USA Basins. Stratigraphically useful palynotaxa include Dictyotriletes bireticulatus , Radiizonates striatus , Schulzospora rara , Granasporites medius , Laevigatosporites minor and Endosporites globiformis . Middle Pennsylvanian palynofloras change through time, being lycopsid dominant in the lower part and more heterogeneous in the middle and upper parts with increased contributions from other Pennsylvanian plant groups. They are correlative with the Duckmantian, Bolsovian and Asturian of western Europe and the Atokan and Desmoinesian of the Eastern and Western Interior mid-continent USA Basins. Stratigraphically useful palynotaxa include Secarisporites remotus , Microreticulatisporites sulcatus , Vestispora fenestrata , Triquitrites sculptilis , Laevigatosporites globosus , Radiizonates difformis , Torispora securis , Triquitrites minutus , Mooreisporites inusitatus , Murospora kosankei , Thymospora pseudothiessenii and Schopfites dimorphus . Upper Pennsylvanian and lower Permian coal beds in the Appalachian Basin, in contrast to their Lower and Middle Pennsylvanian counterparts, are strongly dominated by tree fern spore palynotaxa. Palynofloras correlate with the Stephanian and Autunian of western Europe and the Missourian, Virgilian and Wolcampian of the Eastern and Western Interior mid-continent USA Basins.